U.S. patent application number 14/048884 was filed with the patent office on 2014-09-25 for method for controlling refrigerator.
This patent application is currently assigned to LG ELECTRONICS INC.. The applicant listed for this patent is LG ELECTRONICS INC.. Invention is credited to Yongjoo PARK, Changho SEO, Jaehoon SHIN, Heayoun SUL.
Application Number | 20140284024 14/048884 |
Document ID | / |
Family ID | 49485603 |
Filed Date | 2014-09-25 |
United States Patent
Application |
20140284024 |
Kind Code |
A1 |
SHIN; Jaehoon ; et
al. |
September 25, 2014 |
METHOD FOR CONTROLLING REFRIGERATOR
Abstract
A method for controlling a refrigerator includes driving a
compressor, operating a switching valve to allow a refrigerant to
flow into at least one main expansion valve, opening a cool air
passage connecting a refrigerating compartment to a main evaporator
to cool the refrigerating compartment, operating the switching
valve to switching a flow direction of the refrigerant into at
least one deep-freezing expansion valve when a temperature of the
refrigerating compartment is cooled to a temperature lower than a
set temperature, thereby cooling the deep-freezing storage chamber,
and operating the heater.
Inventors: |
SHIN; Jaehoon; (Seoul,
KR) ; SUL; Heayoun; (Seoul, KR) ; SEO;
Changho; (Seoul, KR) ; PARK; Yongjoo; (Seoul,
KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
LG ELECTRONICS INC. |
Seoul |
|
KR |
|
|
Assignee: |
LG ELECTRONICS INC.
Seoul
KR
|
Family ID: |
49485603 |
Appl. No.: |
14/048884 |
Filed: |
October 8, 2013 |
Current U.S.
Class: |
165/63 |
Current CPC
Class: |
F25B 2600/02 20130101;
Y02B 30/743 20130101; F25D 2700/122 20130101; F25B 2341/06
20130101; F25D 29/00 20130101; F25B 29/003 20130101; F25D 11/022
20130101; F25B 2600/2511 20130101; F25B 2341/0661 20130101; Y02B
40/32 20130101; Y02B 30/70 20130101; F25D 2700/12 20130101; Y02B
40/00 20130101; F25B 2400/01 20130101; F25D 2400/02 20130101; F25B
2600/112 20130101 |
Class at
Publication: |
165/63 |
International
Class: |
F25B 29/00 20060101
F25B029/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 22, 2013 |
KR |
10-2013-0031037 |
Claims
1. A method for controlling a refrigerator comprising: a compressor
to compress a refrigerant; a condenser connected to an outlet-side
of the compressor to condense the refrigerant; a switching valve
connected to an outlet-side of the condenser; an expansion member
connected parallel to an outlet-side of the switching valve, the
expansion member comprising at least one main expansion valve and
at least one deep-freezing expansion valve; a main evaporator to
cool air supplied to at least one of a refrigerating compartment
and a freezing compartment, the main evaporator being connected to
an outlet-side of the at least one main expansion valve; a
deep-freezing evaporator to cool air supplied into a deep-freezing
storage chamber which is maintained at a temperature lower than
that of the freezing compartment, the deep-freezing evaporator
being connected to the outlet-side of the at least one
deep-freezing expansion valve; and a heater contacting the at least
one deep-freezing expansion valve, the method comprising: driving
the compressor; operating the switching valve to allow the
refrigerant to flow into the at least one main expansion valve;
opening a cool air passage connecting the refrigerating compartment
to the main evaporator to cool the refrigerating compartment;
operating the switching valve to switching a flow direction of the
refrigerant into the at least one deep-freezing expansion valve
when a temperature of the refrigerating compartment is cooled to a
temperature lower than a set temperature, thereby cooling the
deep-freezing storage chamber; and operating the heater.
2. The method of claim 1, wherein the operation of the heater is
controlled so that an evaporation temperature (pressure) of the
refrigerant passing through the at least one deep-freezing
expansion valve is lowered to a temperature lower than that of the
refrigerant passing through the at least one main expansion
valve.
3. The method of claim 2, wherein, when the cooling of the
deep-freezing storage chamber starts, the compressor is driven at
an output greater than that in the cooling of the refrigerating
compartment.
4. The method of claim 3, wherein, when the cooling of the
deep-freezing storage chamber starts, the compressor is driven at a
maximum output.
5. The method of claim 4, further comprising: driving a
deep-freezing chamber fan when the compressor is changed in
operation condition, a set time elapses from a time point at which
the switching valve is switched, or the temperature of the
deep-freezing evaporator is lower than the set temperature.
6. The method of claim 5, wherein the heater is operated when the
set time elapses from one of the time point at which the switching
valve is switched, the time point at which the compressor operation
condition is changed, and the time point at which the deep-freezing
chamber fan is operated.
7. The method of claim 6, wherein the compressor and the
deep-freezing chamber fan operation are stopped when the
deep-freezing storage chamber is cooled to a temperature lower than
the set temperature.
8. The method of claim 7, wherein the switching valve is switched
to a position at which the refrigerant is introduced into the at
least one main expansion valve when the compressor operation is
stopped.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims priority benefit to Korean
Patent Application No. 10-2013-0031037 filed on Mar. 22, 2013,
which is herein incorporated by reference in its entirety.
BACKGROUND
[0002] The present disclosure relates to a method for controlling a
refrigerator.
[0003] Refrigerators are home appliances for storing foods at a low
temperature. Generally, a refrigerator includes a refrigerating
compartment for storing foods in a refrigerated state and a
freezing compartment for storing foods in a frozen state.
[0004] Recently, demand for refrigerators including a separate
storage chamber for cooling foods within a short time period to an
ultralow temperature has increased. To achieve the above-described
objects, a separate deep-freezing storage chamber is provided
within a freezing compartment. Also, a structure is provided in
which cool air within a vaporizing chamber is independently
supplied into the deep-freezing deep-freezing storage chamber to
the vaporizing chamber. In the related art, since the cool air
within the vaporizing chamber is separately supplied into only the
deep-freezing storage chamber, the deep-freezing storage chamber
may have a temperature lower than that of the freezing compartment
without having an influence on the temperatures of the freezing
compartment and the refrigerating compartment.
[0005] Generally refrigerators use an R-600a isobutene refrigerant
to lower a temperature of an evaporator to a temperature of about
-40.degree. C. to about -42.degree. C. However, the deep-freezing
storage chamber may require a temperature lower than that of the
evaporator, i.e., a temperature of about -50.degree. C. For this,
it may be insufficient to use only the separate deep-freezing
storage chamber.
[0006] To satisfy the demand of cooling the deep-freezing storage
chamber as described above, a suction pipe connecting the
evaporator to a compressor may heat-exchange with an expansion
valve. In detail, in the case where the suction pipe and the
expansion valve are heat-exchanged to reduce an evaporation
temperature, the refrigerant passing through the expansion valve
may further decrease in temperature to increase a heat absorption
capacity, thereby increasing a cooling ability. However, since an
evaporation pressure itself is not decreased, it may be difficult
to decrease the evaporation temperature.
[0007] To solve the above-described limitation, an expansion valve
having a smaller diameter may be used. In this case, although the
evaporation pressure is decreased, a saturation achievement rate of
the refrigerant may be further reduced when the evaporator absorbs
heat to lower the temperature of the deep-freezing storage chamber
to a set temperature. Specifically, the reduction in the saturation
achievement rate of the refrigerant represents the reduction in an
amount of refrigerant which is saturated to generate a gas by
passing through the evaporator. That is, an amount of liquid
refrigerant introduced into a gas/liquid separator is greater than
that of gas refrigerant. As a result, the possibility in the
introduction of the liquid refrigerant into the compressor may be
further increased. Thus, a condensation pressure and an evaporation
pressure in the whole refrigeration cycle may be further increased.
Furthermore, the liquid refrigerant may be introduced into the
compressor and deteriorate the performance of the compressor or
damage the compressor.
SUMMARY
[0008] One or more embodiments provide a refrigerator in which a
temperature of a deep-freezing storage chamber is further lowered
than that of a deep-freezing storage chamber according to a related
art to minimize damage of a compressor, and a method for
controlling the same.
[0009] In one embodiment, a method for controlling a refrigerator
including: a compressor to compress a refrigerant; a condenser
connected to an outlet-side of the compressor to condense the
refrigerant; a switching valve connected to an outlet-side of the
condenser; an expansion member connected parallel to an outlet-side
of the switching valve, the expansion member including at least one
main expansion valve and at least one deep-freezing expansion
valve; a main evaporator to cool air supplied to at least one of a
refrigerating compartment and a freezing compartment, the main
evaporator being connected to an outlet-side of the at least one
main expansion valve; a deep-freezing evaporator cooling cool air
supplied into a deep-freezing storage chamber which is maintained
at a temperature lower than that of the freezing compartment, the
deep-freezing evaporator being connected to the outlet-side of the
at least one deep-freezing expansion valve; and a heater contacting
the at least one deep-freezing expansion valve includes: driving
the compressor; operating the switching valve to allow the
refrigerant to flow into the at least one main expansion valve;
opening a cool air passage connecting the refrigerating compartment
to the main evaporator to cool the refrigerating compartment;
operating the switching valve to switch a flow direction of the
refrigerant into the at least one deep-freezing expansion valve
when a temperature of the refrigerating compartment is cooled to a
temperature lower than a set temperature, thereby cooling the
deep-freezing storage chamber; and operating the heater.
[0010] The details of one or more embodiments are set forth in the
accompanying drawings and the description below. Other features
will be apparent from the description and drawings, and from the
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a view illustrating a refrigeration cycle of a
refrigerator according to one embodiment.
[0012] FIG. 2 is a p-h diagram for comparing the refrigeration
cycle according to one embodiment to a general refrigeration cycle
according to a related art.
[0013] FIG. 3 is a flowchart illustrating a method for controlling
a temperature of a deep-freezing storage chamber in the
refrigerator according to one embodiment.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0014] In the following detailed description of the preferred
embodiments, reference is made to the accompanying drawings in
which is shown by way of illustration specific preferred
embodiments in which the invention may be practiced. The
embodiments are described in sufficient detail to enable those
skilled in the art to practice the invention, and it is understood
that other embodiments may be utilized. Logical, structural,
mechanical, electrical, and chemical changes may be made without
departing from the spirit or scope of the invention. To avoid
details not necessary to enable those skilled in the art to
practice the invention, descriptions of certain information known
to those skilled in the art may be omitted. The following detailed
description is, therefore, not to be taken in a limiting sense, and
the scope of the present disclosure is defined by the appended
claims.
[0015] Hereinafter, a refrigerator and a method for controlling the
refrigerator according to one embodiment will be described in
detail with reference to the accompanying drawings.
[0016] A method for controlling a refrigerator including: a
compressor to compress a refrigerant; a condenser connected to an
outlet-side of the compressor to condense the refrigerant; a
switching valve connected to an outlet-side of the condenser; an
expansion member connected parallel to an outlet-side of the
switching valve, the expansion member including at least one main
expansion valve and at least one deep-freezing expansion valve; a
main evaporator to cool air supplied to at least one of a
refrigerating compartment and a freezing compartment, the main
evaporator being connected to an outlet-side of the at least one
main expansion valve; a deep-freezing evaporator to cool air
supplied into a deep-freezing storage chamber which is maintained
at a temperature lower than that of the freezing compartment, the
deep-freezing evaporator being connected to the outlet-side of the
at least one deep-freezing expansion valve; and a heater contacting
the at least one deep-freezing expansion valve includes: driving
the compressor; operating the switching valve to allow the
refrigerant to flow into the at least one main expansion valve;
opening a cool air passage connecting the refrigerating compartment
to the main evaporator to cool the refrigerating compartment;
operating the switching valve to switch a flow direction of the
refrigerant into the at least one deep-freezing expansion valve
when a temperature of the refrigerating compartment is cooled to a
temperature lower than a set temperature, thereby cooling the
deep-freezing storage chamber; and operating the heater.
[0017] Also, in the method for controlling the refrigerator
according to one embodiment, the refrigerator may be controlled so
that an evaporation temperature (pressure) of the refrigerant
passing through a deep-freezing expansion value is less than that
of the refrigerant passing through the main expansion valve due to
the operation of the heater.
[0018] Further, when the cooling of the deep-freezing storage
chamber starts, the compressor may be driven at an output torque
greater than that of the compressor in the cooling of the
refrigerating compartment. The compressor may be driven at a
maximum output torque.
[0019] The method for controlling the refrigerator according to one
embodiment may further include driving a deep-freezing chamber fan
when the compressor driving condition is changed, a set time
elapses from a time point at which the switching valve is switched,
or the deep-freezing evaporator is lowered to a set
temperature.
[0020] When the set time elapses from one of the time point at
which the switching valve is switched, the time point at which the
compressor driving condition is changed, and a time point at which
the driving of the deep-freezing chamber fan starts, the heater may
be driven.
[0021] Also, when the deep-freezing storage chamber is cooled to
the set temperature, the compressor and the deep-freezing chamber
fan are stopped.
[0022] When the compressor is stopped, the switching valve is
switched to a position at which the refrigerant is introduced into
the main expansion valve.
[0023] FIG. 1 is a view illustrating a refrigeration cycle of a
refrigerator according to one embodiment.
[0024] Referring to FIG. 1, a refrigeration cycle 10 of a
refrigerator according to one embodiment includes a compressor 11
compressing a refrigerant into a high-temperature high-pressure gas
state; a condenser 12 disposed on an outlet-side of the compressor
11 to phase-change the high-temperature high-pressure gas
refrigerant into a high-temperature high-pressure liquid
refrigerant; expansion valves 14 and 15 disposed on an outlet-side
of condenser 12 to expand the high-temperature high-pressure liquid
refrigerant cooled by passing through condenser 12, thereby
changing the high-temperature high-pressure liquid refrigerant into
a low-temperature low-pressure two-phase refrigerant; and
evaporators 16 and 17 respectively disposed on outlet-sides of
expansion valves 14 and 15 to phase-change the low-temperature
low-pressure two-phase refrigerant which is changed in phase by
passing through expansion valves 14 and 15 into a low-temperature
low-pressure liquid refrigerant.
[0025] Specifically, compressor 11 includes a linear compressor.
Alternatively, compressor 11 may include a fixed speed or inverter
compressor. When compressor 11 includes the linear compressor,
compressor 11 is controlled so that a top dead center operation is
performed in a deep-freezing cooling process.
[0026] Generally, compressor 12 may be accommodated in a machine
room disposed in a rear side of the refrigerator to release heat to
indoor air. Also, a switching valve 13 including a three-way valve
may be disposed between condenser 12 and expansion valves 14 and
15. Switching valve 13 is used for switching a flow direction of
the refrigerant in a structure in which main evaporator 16 is used
for cooling the refrigerating compartment and the freezing
compartment, and deep-freezing evaporator 17 is used for cooling
the deep-freezing storage chamber are connected to parallel to each
other. Here, the three-way valve or a four-way valve may be used
according to the number of evaporators. For example, when one main
evaporator is used, and thus, a cool air passage connecting the
refrigerating compartment to the freezing compartment is switched
to independently control a temperature of each of the storage
compartments, the three-way valve may be used. On the other hand,
in a structure in which an evaporator for the refrigerating
compartment, an evaporator for the freezing compartment, and an
evaporator for the deep-freezing evaporator are separately provided
and connected parallel to each other, the four-way valve may be
applied to switch the flow direction of the refrigerant.
[0027] In the current embodiment for example, the structure in
which one main evaporator 16 is used to cool the refrigerating
compartment and the freezing compartment, and a separate
deep-freezing evaporator 17 for cooling the deep-freezing storage
chamber is parallely connected to main evaporator 16 will be
described as an example. Thus, main expansion valve 15 and
deep-freezing expansion valve 14 may be respectively disposed on
inlet-sides of main evaporator 16 and deep-freezing evaporator 17,
and expansion valves 14 and 15 are connected in parallel to the
outlet-side of switching valve 13.
[0028] Also, a separate heater 18 may be mounted on an outer
circumferential surface of deep-freezing expansion valve 14 to
reduce a temperature of the refrigerant passing through
deep-freezing expansion valve 14 to a temperature lower than that
of the freezing compartment. Heater 18 is operated in an operation
mode for cooling the deep-freezing storage chamber. When the
deep-freezing storage chamber is cooled to a set temperature,
heater 18 may be stopped.
[0029] Also, a condensation fan and an evaporation fan may be
respectively mounted outside condenser 12 and evaporators 16 and 17
to heat-exchange the indoor air with the refrigerant or air within
the storage chamber with the refrigerant.
[0030] FIG. 2 is a p-h diagram for comparing the refrigeration
cycle according to an embodiment to a general refrigeration cycle
according to a related art.
[0031] Referring to FIG. 2, in the general refrigeration cycle
according to the related art, and compression, condensation,
expansion, and evaporation are performed in an order of points a,
b, c, and d.
[0032] On the other hand, in the refrigeration cycle according to
the present disclosure, i.e., the refrigeration cycle including
eater 18 on the outer circumferential surface of deep-freezing
expansion valve 14, compression, condensation, expansion, and
evaporation are performed in an order of points e, f, c, and g.
[0033] As shown in the p-h diagram, when heater 18 mounted on
deep-freezing expansion valve 14 is driven, the refrigerant passing
through deep-freezing expansion valve 14 may be dropped to an
evaporation pressure lower than that in the refrigerant cycle
according to the related art. Specifically, since the evaporation
pressure is lowered, the evaporation temperature is lowered. Thus,
since the evaporation temperature is lowered, cool air within the
deep-freezing storage chamber may be lower in temperature than that
of cool air according to the related art.
[0034] The general refrigeration cycle according to the related art
in the p-h diagram of FIG. 2 represents a cycle diagram when any
heat-exchange member is not provided to the expansion valve. In a
case of a structure in which a suction pipe is heat-exchanged with
the expansion valve, heat may be transferred from the refrigerant
passing through the expansion valve to the refrigerant passing
through the suction pipe, an amount of gas refrigerant of the
refrigerant introduced into the compressor may be increased. Then,
the refrigerant passing through the expansion valve may be
decreased in temperature. Thus, an enthalpy line (c-d line) of the
refrigerant may be further shifted to the left in the p-h diagram.
As a result, an enthalpy valve of the refrigerant at an inlet of
the evaporator may be decreased. That is, an amount of heat
absorbed into the evaporator may be increased to increase cooling
capacity. However, although the heat exchange may be performed
through the suction pipe, since the evaporation pressure is not
changed, it may be difficult to further reduce the temperature of
the cool air within the deep-freezing storage chamber even though
the cooling capacity is increased.
[0035] Also, in a case where the deep-freezing expansion valve has
a diameter less than that of the main expansion valve, a
refrigerant state point (point d) when the expansion is completed,
i.e., an evaporation pressure at the inlet of the deep-freezing
evaporator may be further decreased, and also, an enthalpy valve at
the deep-freezing evaporator may be increased. That is, in the p-h
diagram, the point d may be shifted down and to the right. As a
result, the refrigerant may be further decreased in temperature to
decrease the temperature of the deep-freezing storage chamber.
However, due to the decrease in the temperature of the
deep-freezing storage chamber, an amount of refrigerant which is
changed in phase from the liquid refrigerant to the gas refrigerant
in the refrigerant passing through the evaporator may be reduced.
That is, if it is assumed that the refrigerant passing through the
evaporator absorbs energy having the same heat from the indoor air,
an amount of refrigerant which is changed in phase from the liquid
refrigerant to the gas refrigerant may be reduced. This may
represent the reduction in a saturation achievement rate of the
refrigerant. As a result, possibility of the introduction of the
liquid refrigerant into the compressor may be further
increased.
[0036] As proposed in the current embodiment, when heater 18 is
mounted on the surface of deep-freezing expansion valve 14, outlet
point d of the deep-freezing expansion valve (or the outlet point
of the deep-freezing evaporator) may be moved to point g in an
ideal state. In an actual refrigeration cycle, point g may be
located at a point that is further shifted to the right.
[0037] If it is assumed that the evaporator absorbs the energy
having the same heat, quality of the refrigerant at the inlet of
the compressor, i.e., quality of the refrigerant at an inlet of a
gas/liquid separator may be further increased in the current
embodiment when compared to the case in which the expansion valve
is changed in diameter. This may represent that the saturation
achievement rate of the refrigerant is not reduced. Thus, the
possibility of the introduction of the liquid refrigerant into the
compressor may be significantly decreased.
[0038] Hereinafter, a method for controlling a temperature of the
deep-freezing storage chamber in the refrigerator having the
refrigeration cycle according to one embodiment will be described
in detail with reference to the flowchart.
[0039] FIG. 3 is a flowchart illustrating a method for controlling
a temperature of the deep-freezing storage chamber in the
refrigerator according to an embodiment.
[0040] Referring to FIG. 3, a compressor is driven (S11). Here, a
pre-cooling process for cooling a refrigerating compartment to a
temperature lower than a set temperature may be previously
performed.
[0041] Specifically, a switching valve, i.e., a three-way valve may
be opened while the compressor is driven to control a refrigerant
passage so that a refrigerant flows toward a main evaporator 16
(S12). Then, the refrigerant compressed by compressor 11 passes
through a condenser 12 and then is introduced into a main expansion
valve 15 and thus is expanded. The expanded low-temperature
low-pressure two-phase refrigerant is introduced into a main
evaporator 16 (S13) to decrease a temperature of the evaporator to
a temperature of about -42.degree. C. In this state, a damper (not
shown) provided in a cool air passage may be operated to open a
refrigerating compartment passage, and simultaneously, a
refrigerating compartment fan may be operated (S14). Here, if the
refrigerating compartment fan is not separately provided, a cooling
fan disposed on a side of main evaporator 16 may be driven.
[0042] If the refrigerating compartment fan or the cooling fan
disposed on the side of main evaporator 16 is operated, the
refrigerant cooled in the evaporator may be guided to the
refrigerating compartment along the refrigerating compartment
passage. As a result, an internal temperature of the refrigerating
compartment may be gradually decreased.
[0043] Whether the refrigerating compartment temperature reaches a
set temperature (T.sub.R-a).degree. C. may be determined by a
temperature sensor and a controller (S15). In the control method
according to the current embodiment, the refrigerating compartment
temperature may be lowered to a temperature about (a).degree. C.
less than the set temperature to perform a deep-freezing cooling
process, thereby preventing a load of the refrigerating compartment
from being increased in the deep-freezing cooling process. Thus,
the controller may maintain the cooling of the refrigerating
compartment until a temperature signal transmitted from a
refrigerating temperature sensor reaches a temperature slightly
lower than a set temperature T.sub.R.
[0044] Specifically, when it is determined that the refrigerating
compartment temperature reaches a temperature lower than the set
temperature T.sub.R, the refrigerating compartment passage may be
closed by the damper, and then the operation of the refrigerating
compartment fan is stopped (S16). Here, if the separate
refrigerating compartment fan is not provided, and only the cooling
fan of the main evaporator is provided, the cooling fan may be
continuously operated to cool a freezing compartment.
[0045] Also, although only the overcooling process for further
lowering the temperature of the refrigerating compartment to a
temperature lower than the set temperature T.sub.R is performed,
the present disclosure is not limited thereto. For example, an
overcooling process for further lowering a temperature of the
freezing compartment may be performed together. In a case of the
freezing compartment, since a temperature within the refrigerator
is maintained to a temperature lower than a freezing temperature,
foods are not significantly changed in phase due to the
overcooling. Thus, even though the freezing compartment temperature
is in the present set temperature state, the cool air may be
supplied into the freezing compartment in the overcooling process
for the refrigerating compartment. Alternatively, the supplying of
the cool air into the freezing compartment may be blocked to save
on power consumption.
[0046] When the overcooling process for the refrigerating
compartment is ended, the three-way valve may be switched (S17) to
allow the refrigerant to flow toward deep-freezing evaporator 17,
thereby performing a deep-freezing cooling process. Here, when the
deep-freezing cooling process starts, the operation condition of
compressor 11, which is performed in the overcooling process for
the refrigerating compartment may be changed. That is, to cool the
deep-freezing storage chamber to the set temperature for a short
time, compressor 11 may be converted into a maximum output
operation mode (S19). For example, when compressor 11 includes a
linear compressor, the operation mode may be converted from a
normal operation condition to a top dead center operation
condition.
[0047] Here, when a deep-freezing chamber fan is operated just when
the deep-freezing cooling process is performed, hot air may be
guided into the deep-freezing storage chamber to deteriorate
deep-freezing performance. Thus, it may be important that the
deep-freezing chamber fan is operated in a state where
deep-freezing evaporator 17 is sufficiently cooled.
[0048] Thus, a process for determining whether a set time elapses
from a time point at which an operation condition of the compressor
is converted into the maximum output operation condition or a time
point at which the three-way valve is switched, or whether the
evaporator temperature transmitted from the temperature sensor
attached to deep-freezing evaporator 17 reaches a set temperature
T.sub.d may be performed (S20). If it is determined that the set
time elapses, or the deep-freezing evaporator temperature reaches
the set temperature T.sub.d, a deep-freezing chamber passage may be
opened by an operation of the damper, and simultaneously, the
deep-freezing chamber fan may be operated (S21).
[0049] Also, when the set time elapses from one of the time point
at which the switching valve is switched, the time point at which
the compressor is changed in driving condition, and time point at
which the driving of the deep-freezing chamber fan starts, the
heater may be turned on (S22). According to this system, a time
point at which the deep-freezing chamber temperature is cooled to a
temperature lower than the refrigerating compartment temperature,
i.e, a time point at which the deep-freezing cooling is realized
may be a time point after the heater is operated.
[0050] Also, if it is determined that the deep-freezing storage
chamber temperature is cooled to a set temperature T.sub.c (S23),
the compressor, the deep-freezing chamber fan, and the heater may
be stopped in operation (S24). Here, switching valve 13 may return
to its original position, i.e., a position at which the refrigerant
is introduced toward main expansion valve 15.
[0051] According to the above-described control method, since the
deep-freezing storage chamber temperature is quickly cooled to a
temperature significantly lower than the freezing compartment
temperature, the compressor is not affected in performance and
strength thereof.
[0052] According to the method for controlling the refrigerator
including the above-described embodiments, the separate heater may
be provided to the expansion valve connected to the inlet-side of
the evaporator for the deep-freezing storage chamber to further
decrease the evaporator pressure when compared to that in the
related art. Thus, the evaporator may be lowered up to a
temperature of a maximum -50.degree. C. Additionally, the
deterioration in the saturation achievement rate of the refrigerant
which occurs when the expansion valve is changed in diameter do not
occur, preventing the compressor from being deteriorated in
performance or damaged.
[0053] Although embodiments have been described with reference to a
number of illustrative embodiments thereof, it should be understood
that numerous other modifications and embodiments can be devised by
those skilled in the art that will fall within the spirit and scope
of the principles of this disclosure. More particularly, variations
and modifications are possible in the component parts and/or
arrangements of the subject combination arrangement within the
scope of the disclosure, the drawings, and the appended claims. In
addition to variations and modifications in the component parts
and/or arrangements, alternative uses will also be apparent to
those skilled in the art.
* * * * *